Mio starts getting pumped up for she is trying to design a Best Friends Rare dress for Pure Palette. When Mio reaches a wall in designing, Aine invites Mio on a mystery tour planned by Aine herself. Walking along the lands of the forest, they reach the place known as "Hero's Bridge". And to Aine, this bridge that was a part of her childhood memories means?

The school's biggest event of the summer, the Star Harmony Cup, is about to begin. The favorites to win the event, Honey Cat, are having a training camp in the gym so that they can pull off a Friends Appeal worthy of their dresses. The two undergo lessons while also busy with work. Can they show off the results of their training at the Star Harmony Cup?